Plasma devices refer to devices configured for generating plasma. Such plasma can be used, for example, in surgery for destruction (dissection, vaporization) and/or coagulation of biological tissues.
As a general rule, such plasma devices have a long and narrow end that can be easily held and pointed toward a desired area to be treated, such as bleeding tissue. Plasma is discharged at a distal portion of the device. The high temperature of plasma allows for treatment of the affected tissue.
WO 2004/030551 (Suslov) discloses a plasma surgical device according to prior art. This device comprises an anode, a cathode, and a gas supply channel for supplying plasma-generating gas from the plasma-generating system. The device further comprises a number of electrodes arranged upstream of the anode. A housing of an electrically conductive material which is connected to the anode encloses the device and forms the gas supply channel.
Owing to the recent developments in surgical technology, laparoscopic (keyhole) surgery is being used more often. Performing laparoscopic surgery requires devices with small dimensions to allow access to the surgical site without extensive incisions. Small instruments are also advantageous in any surgical operation for achieving good accuracy.
When making plasma devices with small dimensions, there is often a risk that due to the temperature of the cathode, which in some cases may exceed 3000° C., other elements in the proximity of the cathode would be heated to high temperatures. At these temperatures, there is a risk that these elements may be degraded, thus, contaminating the generated plasma. Contaminated plasma may introduce undesirable particles into the surgical area, which may be harmful to a patient.
Thus, there is a need for improved plasma devices, in particular plasma devices with small dimensions that can produce high temperature plasma.